1. Field of the Invention
The invention relates to a process for controlling foam in aqueous media. More specifically, the invention relates to a process for controlling foam using alkadienyl ethers of sugars and sugar derivatives.
2. Description of the Related Art
In many branches of industry, the control and prevention of foam development plays an important role to guarantee a smooth manufacturing process and perfect products. The foams developing due to the presence of surface-active substances are especially disturbing in waste water treatment, manufacturing and use of dispersion dyes, bleaching and dyeing of textiles, enzymatic processes, textile and paper printing, paper manufacturing, as well as preparation of sugar beets. Foam problems can be prevented by adding foam inhibitors before foam develops, or existing foam can be destroyed by adding defoamers. Both foam inhibitors and defoamers comprise anti-foaming agents in this sense.
It is expected of anti-foaming agents that they will be effective and exhibit long-term efficacy when used in small quantities. In addition, for use in the food sector, they must be odorless, tasteless, physiologically safe, and removable during processing of the food product. Since anti-foaming agents usually enter the waste water, they should also be readily bio-degradable. Previously, polyalkylene glycols or fatty acids of poly-alkylene glycols have been used as foam inhibitors and defoamers. A number of typical anti-foaming agents with patent citations and application areas are presented in Ullmann's Encyclopedia of Industrial Chemistry (Ullmanns Encyklopadie der techn. Chemie), Vol. 20 (4th new and expanded edition), 1981, pp. 412-414.
The relatively slow biodegradability of propoxylated anti-foaming agents has been found to be a disadvantage. To be sure, ethoxylated products are more readily biodegradable, but as a result of their manufacturing process, they sometimes contain very small amounts of dioxane. Although a large number of anti-foaming agents are available, the expert continues to have a need for such agents that show improved long-term efficacy.
The present invention provides potentially biodegradable anti-foaming or foam-controlling agents which are effective in the short term and maintain their efficacy over extended periods when used in small quantities.